I used to have lots of bikes, but then realized I had 2 needs: commuting/kid hauling, and long rural paved road rides.

I sold my tri-bike and my road race bike, and kept my cross bike and my mtn bike. The mtn bike is for commuting. Its a 90s era steel masterpiece. I use it to commute because cheap tires are abundant (even with studs), and I can add a rack, wire my light/battery setup and leave it on there with no concerns, and my 7 speed setup is pretty indestructible.

My other bike is a converted JTS with campy components and Krysrium wheels. I figured this was the better option for the long rural rides, and I wouldn't trust it to be locked up at work, exposed to the elements.